A dental articulator is used to connect dental models of upper and lower sets of teeth and to simulate the movement of the patient's jaw. Early articulators were large, cumbersome devices, usually made of metal, and the teeth models were attached to them with plaster. The next generation of articulators were also metal, but they were smaller and easier to manipulate. The models still attached to them with plaster, however, and the process of articulation remained time-consuming and messy. The most common articulators currently used in the field are made entirely of plastic. Models are attached to the articulators with super glue instead of plaster, and they are much easier to handle and work. The current system, however, does offer opportunities for improvement.
The VERTEX articulator system sold by Ceramco of Burlington, N.J., represents the type of articulators currently used in the art. See FIG. 1. The VERTEX system consists of three parts: plastic sockets (1), plastic hinges (2) having mounted plastic balls (3) matching the plastic sockets and rubber base molds (4 and 5). The rubber base mold is customarily in the form of a half mold (4) which allows the modeling of an entire set of upper or lower teeth, or a quarter mold (5), which allows only modeling of one half of a set of upper or lower teeth. Plaster is poured into the rubber base mold (4 or 5), model teeth (not shown) are anchored in the upper surface of the uncured plaster and then the plaster is allowed to set. After curing, the upper teeth hardened base and lower teeth hardened base containing the model teeth are removed from their respective rubber molds. The plastic sockets (1) are then glued to the ends of an upper teeth hardened base and a lower teeth hardened base. The plastic balls (3) on the hinges (2) are then inserted into the sockets (1) and the model teeth in the molds are aligned to match the natural bite (occlusion) of the subject. Once the model teeth are properly aligned, the balls (3) are glued into place in the sockets (1) to fix them in that alignment, while the hinges (2) are left freely moving to represent opening and closing of the mouth.
This system suffers from several drawbacks. The super glue used (cyano acrylate) is hazardous and unpleasant to work with. The entire hinge unit, including the sockets, easily breaks off of the hardened base, and the rubber base molds accumulate bits of hardened plaster over time, particularly in its corners, which mar the surface of the base units made in them and makes removal of the hardened base unit increasingly difficult over time.
Accordingly, it is an object of this invention to provide a low cost, plastic, dental-model articulator which is less likely to break away from the dental model base.
It is a further object of this invention to provide a low-cost, plastic, dental-model articulator which does not require the use of glue to assemble the finished, articulated dental model.
It is yet another object of this invention to provide a method of forming an articulated dental model with fewer mold marks and improved strength in the attachment of the articulating hinge to the upper and lower teeth bases.
It is still another object of this invention to provide a significant improvement in the physical protection of the model base and the model teeth.